Closures are recursively reachable

compiler/rustc_passes/src/reachable.rs

@@ -157,6 +157,7 @@ impl<'tcx> ReachableContext<'tcx> {
                 }
                 hir::ImplItemKind::Type(_) => false,
             },
+            Node::Expr(&hir::Expr { kind: hir::ExprKind::Closure(..), .. }) => true,
             _ => false,
         }
     }

tests/ui/cross-crate/auxiliary/static_init_aux.rs

@@ -3,6 +3,12 @@ pub static F: fn() = f;
 pub static G: fn() = G0;
 pub static H: &(dyn Fn() + Sync) = &h;
 pub static I: fn() = Helper(j).mk();
+pub static K: fn() -> fn() = {
+    #[inline(never)]
+    fn k() {}
+    #[inline(always)]
+    || -> fn() { k }
+};
 
 static X: u32 = 42;
 static G0: fn() = g;

tests/ui/cross-crate/static-init.rs

@@ -8,6 +8,7 @@ static F: fn() = aux::F;
 static G: fn() = aux::G;
 static H: &(dyn Fn() + Sync) = aux::H;
 static I: fn() = aux::I;
+static K: fn() -> fn() = aux::K;
 
 fn v() -> *const u32 {
     V
@@ -19,4 +20,5 @@ fn main() {
     G();
     H();
     I();
+    K()();
 }